Add the ginger and one tablespoon of soy, and fry for three minutes more, stirring very often, until the aubergine is a dark golden brown. Remove the aubergine from the wok, wipe the pan clean, then return it to the heat. Put the cumin seeds in the hot pan and, taking care not to burn them, dry fry for around 30 seconds, until fragrant, then tip into a saucer.